JP2943754B2 - Radar equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse generator used in a transmitter for a pulse radar device, and more particularly to a pulse generator and a radar device for generating a square wave having an arbitrary pulse width and a sharp rise and fall. About.

[0002]

2. Description of the Related Art In order to increase the detectable distance of a pulse radar apparatus, it is necessary to increase the peak power of a transmission signal or to increase the transmission pulse energy by increasing the transmission pulse width. In order to increase the peak power of the transmission signal, it is necessary to increase the size and the voltage of the transmitter and peripheral devices. Therefore, in recent years, a transmitter using a pulse compression technique that transmits a pulse wave with an increased pulse width and compresses the pulse width of a received pulse to obtain a required resolution has become common. Further, in order to improve the minimum detection distance performance, a pulse radar apparatus adopting a combined system in which a narrow pulse for a short distance and a wide pulse for a long distance are transmitted in combination has been put to practical use. Furthermore, recently, a pulse radar device that changes a transmission pulse width has been put to practical use.

An example of a transmitter used in this type of pulse radar device is disclosed in Japanese Patent Application Laid-Open No. Sho 62-57314. As shown in FIG. 3, a transmitter disclosed in the publication includes a transmission tube 61, a beam power supply 65, and a collector power supply 6.
4. It basically comprises a pulse generator 66, an RF exciter 62 and an isolator 63. The transmission tube is composed of a grid modulation type amplification tube such as a traveling wave tube (TWT), a klystron (KLYSTRON), etc., and a main body 61 to be grounded.
a, an RF circuit 61c having the same potential, and an RF circuit 61c including a grid 61d and a cathode 61e.
An RF signal is input to the grid 61d side (input side) via the exciter 62, and an isolator 63 is disposed on the collector 61b side (output side).

The collector 61b has a power supply 64 for the collector.
, A required positive DC voltage is applied, and a required negative DC voltage (E0) is applied to the cathode 61e by the beam power supply 65. A positive voltage (E1) and a negative bias voltage (E2) for determining the pulse amplitude based on the cathode potential (E0) are applied to the grid 61d from a pulse generator as shown in FIGS. .

The pulse generator shown in FIG. 4 is an example of a pulse generator for transmitting one pulse wave. In this case, a pulse transformer for transmitting a desired pulse width is selected, and only a predetermined pulse width can be generated. This pulse generator includes two DC power supplies 41 and 42 connected in series, a switcher 43, a pulse transformer 45,
It is basically composed of a drive circuit 46 and a tail vital circuit 47.

The positive terminal of the DC power supply (terminal voltage E1) 41 is connected to the power input side of the switch 43, and the output terminal of the switcher 43 is connected to the grid 61d. The negative terminal of the DC power supply 41 is connected to the DC power supply (terminal voltage E
2) A resistor 47 is connected between the negative terminal of the DC power supply 42 and the output terminal of the switcher 43, together with the positive terminal of 42 and the negative terminal of the beam power supply 65. Further, a tail bitter circuit 48 is connected to the resistor 47 in parallel. The pulse transformer 45 has a plurality of secondary windings, and each of the secondary windings is connected to each of the switching elements 44 constituting the switcher 43. Also,
A driving circuit 46 for energizing the pulse transformer 45 is connected to the primary winding of the pulse transformer 45, and the driving circuit 46
Receives a drive signal a.

The drive signal a is, for example, a signal in which one short pulse and one long pulse repeat at a period T. The drive circuit 46 has a pulse transformer 45 in synchronization with each pulse of the drive signal a. Energize. Therefore, each switching element 4
4,44, ... In this case, the drive signal a is turned on only during the pulse widths of the short pulse and the long pulse of the drive signal a, and is turned off during the pulse pause.

The pulse generator shown in FIG. 5 has a pulse transformer corresponding to each pulse width for a narrow pulse and a wide pulse. In the pulse transformer for narrow pulse, a pulse with sharp rising and falling characteristics is input to the switching element by emphasizing the high frequency characteristics. In the pulse transformer for wide pulse, a wide pulse having a flat portion without sag by emphasizing the low frequency range of the frequency characteristic is input to the switching element. The outputs of the respective pulse transformers are added by an adder circuit arranged in a time series, and the switching elements are activated to optimize the output pulse waveform to a square wave.

The pulse generator receives a short pulse drive signal SP as a first pulse and a long pulse drive signal LP as a second pulse as drive signals for generating a required pulse, respectively. Each drive signal SP and L
For P, a short-pulse drive circuit 31 and a pulse transformer 32 and a long-pulse drive circuit 33 and a pulse transformer 34 are separately provided. And arranged in a time-series manner and input to the switching element.

Here, the pulse transformer 32 transmits a short pulse signal, and its frequency characteristic is formed by emphasizing a high frequency, and a short pulse having a sharp rising and falling characteristic is formed by each of the switching elements 44, 44. , ...
Is input to

The frequency characteristic of the pulse transformer 34 is such that it transmits a long pulse signal, and the frequency characteristic of the pulse transformer 34 is such that the low frequency is emphasized. , ... are input. Each switching element 44 has an extremely wide frequency characteristic. As a result, the transmission tube 6
A grid drive pulse applied to one grid 61d,
That is, as shown in FIG. 2, the output pulse is outputted as a short pulse with a sharp rising and falling pulse, and as a long pulse, a pulse without a sag in a flat portion.

[0012]

In the grid modulation type transmitter used in the above-described pulse radar device, the transmission pulse waveform is the waveform of a grid drive pulse applied to the grid (rise, fall, sag, libble). Etc.). The waveform of the grid drive pulse is
Ideally, the pulse waveform must be a square wave. That is, as shown in FIG. 6, the RF output waveform has a delay time (t1 and t1) due to the rise and fall characteristics of the grid drive pulse e in response to the drive signal a and the trigger signal d.
2) occurs, and there is a problem in the pulse radar device that the timing control becomes complicated.

In the pulse generator used in the grid modulation type transmitter, for example, in order to generate a square wave having a pulse width of several μS to several mS, a means for transmitting a drive signal to the switcher and a switcher having a wide band. Need to be However, there is no problem since the switcher is originally a wide band, but it is difficult to widen the band width of the pulse transformer used as a means for transmitting a pulse wave to the switcher since the pulse waveform is composed of a DC component and a high frequency component. It is. This is because the inductance, turn ratio, magnetic core, and the like of the pulse transformer have frequency characteristics. Due to these characteristics, (a) in response to the drive signal input pulse as shown in FIG. ) When the high frequency is emphasized, (b) when the high frequency is emphasized, the rising and falling characteristics are distorted, so that it is difficult to generate a square wave with an arbitrary pulse width. Was.

As described above, in order to generate a square wave pulse signal with an arbitrary pulse width, the conventional pulse generator needs to mount a plurality of pulse transformers selected for the pulse width. Since the rise and fall times are determined by the characteristics of the implemented pulse transformer, a pulse waveform with steep rise and fall times for any pulse width that is continuous or selected from a narrow pulse to a wide pulse is selected. It was difficult to output.

An object of the present invention is to provide a pulse generator capable of generating a square wave having an arbitrary pulse width and generating a square wave having sharp rising and falling characteristics.

[0016]

According to the present invention, there is provided a pulse generator for amplifying an input pulse.
A pulse driver that sends information on the pulse width of the input pulse, a pulse transformer that receives the output of the pulse driver as an input, and outputs a pulse that emphasizes a low-frequency region, and a rise and fall of the output of the pulse transformer A trigger generating circuit for storing time information in advance and transmitting a pulse waveform correction trigger signal corresponding to the stored information; and a rising and falling time of a pulse wave transmitted by the pulse transformer by a trigger of the trigger generating circuit. A pulse generator having a pulse waveform correction circuit for correcting,
A radar pulse generator for transmitting a radar pulse generated based on an output pulse from the pulse generator.

[0017]

[0018]

[0019]

[0020]

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a pulse generator according to the present invention. The pulse generator shown in FIG. 1 receives an input pulse A having an arbitrary pulse width, obtains an output B amplified to a level for driving the pulse transformer 3, and obtains a trigger generation circuit 2
A pulse driver 1 for transmitting input pulse width information to a pulse transformer 3, a pulse transformer 3 for emphasizing a low-frequency region, and information on rising and falling times of pulses of the pulse transformer 3 are stored, and a trigger signal D corresponding to the information is stored. It comprises a trigger generation circuit 2 to be generated and a pulse waveform correction circuit 4 for correcting a pulse as an optimal square wave from a trigger of the trigger generation circuit 2 and a pulse E from the pulse transformer 3. The output from the pulse waveform correction circuit 4 drives the transmission tube 6 via the switcher 5.

FIG. 2 is a time chart showing the operation of the pulse generator shown in FIG. In the pulse driver 1 to which the input pulse A having an arbitrary pulse width is input, the output B is obtained by amplifying the input pulse to a level that can drive the pulse transformer 3.
Is output to the pulse transformer 3 and the pulse width information of the input pulse A is sent to the trigger generation circuit 2.

The pulse transformer 3 optimizes the sag characteristic of a wide pulse, and is selected so as to have a characteristic in which a low-frequency region is particularly emphasized. By doing so, the output B from the pulse driver 1 is output to the pulse transformer 3 shown in FIG.

The trigger generation circuit 2 stores information on the rise and fall times of the pulse transformer 3 in advance, generates a trigger pulse D having a width corresponding to the rise and fall times of the input pulse width, and generates a pulse waveform. It is sent to the correction circuit 4.

The pulse waveform correction circuit 4 operates so as to correct the rise time and the fall time based on the output signal D from the trigger generation circuit 2 and sends it to the switcher 5 as a desired square wave.

[0026]

As described above, according to the pulse generator of the present invention, it is possible to generate a pulse wave having an arbitrary pulse width and a sharp rise and fall time.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram illustrating an embodiment of a pulse generator according to the present invention.

FIG. 2 is a time chart for explaining the operation of the pulse generator shown in FIG.

FIG. 3 is a configuration diagram of a grid modulation type transmitter.

FIG. 4 is a configuration block diagram of a conventional pulse generator.

FIG. 5 is a block diagram showing another configuration of a conventional pulse generator.

FIG. 6 is an operation explanatory diagram of the grid modulation type transmitter.

FIG. 7 is a diagram showing an output waveform of a conventional pulse generator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pulse driver 2 trigger generation circuit 3 pulse transformer 4 pulse waveform correction circuit 5 switcher 6 transmission tube 31, 33 drive circuit 32, 34 pulse transformer 35 addition circuit 43 switcher 44 switching element

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01S 7/00-7/42 G01S 13/00-13/95 H03K 5/01

Claims (1)

(57) [Claims] An input pulse is amplified and the input pulse is amplified.
A pulse driver for transmitting information of a pulse width;
Input of the output of the
Output pulse transformer and output of this pulse transformer
The rise and fall time information of
The trigger signal for pulse waveform correction corresponding to the stored information
And a trigger generating circuit for outputting the trigger.
Of the pulse wave transmitted by the pulse transformer
Pulse waveform compensation to correct rise and fall times
A pulse generator having a positive circuit and the pulse generator
The radar pulse generated based on the output pulse
Outgoing radar pulse generator
Radar equipment.